Dual mode condensing cycle

Abstract

An air conditioning system is provided that includes first and second turbines and a compressor. The second turbine is in fluid communication with a pack outlet. A passage fluidly connects the first turbine and the pack outlet. A valve is associated with the passages and is movable between open and closed positions. In the open position, the valve permits flow through the passageway from the first turbine directly to the pack outlet thereby bypassing the second turbine and reducing the resistance to the flow through the system. The valve is opened at higher altitudes to change the typical series fluid connection between the turbines to a parallel fluid connection. In this configuration, the air conditioning system operates more efficiently using reduced air pressure provided to the system. Another valve is also opened to permit additional reduction in the air pressure required.

1. An air conditioning system comprising:
 first and second turbines and a compressor, the second turbine in fluid communication with a pack outlet; 
 a passage fluidly connecting the first turbine and the pack outlet; and 
 a valve associated with the passage and movable between first and second positions, the second position selectively increasing flow through the passage from the first turbine to the pack outlet relative to the first position to bypass the second turbine reducing pressure required from an air source. 
 
   
   
     2. The air conditioning system according to  claim 1 , wherein the first position is an opened position and the second position is a closed position, the opened and closed position respectively corresponding to high and low altitude modes. 
   
   
     3. The air conditioning system according to  claim 2 , comprising a heat exchanger with fluid flowing from the heat exchanger to the second turbine through an open chiller diverter valve in the high altitude condition, the chiller diverter valve closed in the low altitude mode. 
   
   
     4. The air conditioning system according to  claim 3 , wherein the high altitude mode includes first and second flow paths, the first flow path including fluid flowing from the heat exchanger to the compressor and returning to the heat exchanger, the fluid flowing from the heat exchanger through conditioning circuits to the first turbine into the pack outlet through the open first turbine dump valve. 
   
   
     5. The air conditioning system according to  claim 2 , wherein the low altitude mode includes a first and second flow paths, the first flow path including fluid flowing from the heat exchanger to the compressor and returning to the heat exchanger, fluid flowing from the heat exchanger through the conditioning circuits to the first turbine, the flow blocked by a closed first turbine dump valve thereby directing flow from the first turbine through the conditioning circuits to the second turbine and out the pack outlet, the second flow path including flowing the fluid through the heat exchanger past a closed chilled diverter valve through the conditioning circuits to the second turbine and out the pack outlet. 
   
   
     6. The air conditioning system according to  claim 4 , comprising a heat exchanger assembly including primary, secondary, and chiller heat exchangers providing first and second flow paths. 
   
   
     7. The air conditioning system according to  claim 4 , comprising a conditioning circuit including a reheater, a condenser, and a water collector. 
   
   
     8. The air conditioning system according to  claim 5 , comprising a heat exchanger assembly including primary, secondary, and chiller heat exchangers providing first and second flow paths. 
   
   
     9. The air conditioning system according to  claim 5 , comprising a conditioning circuit including a reheater, a condenser, and a water collector. 
   
   
     10. The air conditioning system according to  claim 5 , wherein flow from the first turbine is blocked preventing flow from a first turbine outlet to the second turbine. 
   
   
     11. The air conditioning system according to  claim 2 , wherein pressure from the air source is greater in the low altitude mode than in the high altitude mode in response to the opened position. 
   
   
     12. The air conditioning system according to  claim 2 , wherein the turbines are fluidly connected in series in the low altitude mode. 
   
   
     13. The air conditioning system according to  claim 2 , wherein the turbines are fluidly connected in parallel in the high altitude mode. 
   
   
     14. A method of controlling an air conditioning system comprising:
 a) flowing fluid from a first turbine to a second turbine; 
 b) moving a valve from a first position to a second position; 
 c) diverting flow from the first turbine around the second turbine to a pack outlet in response to performing step b); and 
 d) reducing resistance to flow through the system in response to performing step c).